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TMS320F280025-Q1: unused pins reset condition

Simon Jagla
Expert 8685 points

Part Number: TMS320F280025-Q1

Hi Colleagues,

can you clarify the wording of the chapter 8.6 Internal Pullup Configuration Requirements of the TRM. 

It says: "On reset, GPIOs are in input mode and have the internal pullups disabled. An un-driven input can float to a midrail voltage and cause wasted shoot-through current on the input buffer."

we have customers concerns that this can be a dangerous condition. Since you cannot configure the pull ups after reset instantly the controller will be in this condition at every startup for a very short time. can you explain what can happen in this condition?

BR Simon

  • 0
    TI__Mastermind 19795 points

    Hi BR,

    This is essentially describing that since the pull-ups are disabled on startup, if there is no EXTERNAL pullup/down on the pin, then the pin will essentially be in a "floating" state.

    What can happen depends on what the GPIO was connected to. To avoid problems, an external pull up or pull down can be used. Pull up vs pull down must be decided by the particular connection for each GPIO.

    Regards,

    Vince